1. Field of the Invention
The present invention relates to a capsule guiding system and a capsule guiding method for guiding, by a magnetic force, a capsule medical device that is introduced into a subject, such as a patient.
2. Description of the Related Art
In the field of endoscopy, capsule endoscopes that can be introduced into the alimentary canal of a subject, such as a patient, have been used. A capsule endoscope is swallowed by a subject, then takes images of the internal organs of the subject (hereinafter, sometimes referred to as an in-vivo image) while moving through the alimentary canal by peristalsis, and wirelessly transmits the taken in-vivo images to a receiving device outside the subject. The capsule endoscope sequentially takes in-vivo images of the subject over a period of time until it is naturally excreted to the outside of the subject.
Capsule guiding systems for guiding (magnetic guiding) a capsule endoscope that is introduced into a subject by a magnetic force have been also proposed. Generally, in a capsule guiding system, a capsule endoscope provided with a spiral protrusion on the outer circumference of its capsule-shaped casing incorporating a magnet that is magnetized in a radial direction is introduced into the alimentary canal of a subject. By applying a rotation magnetic field that is generated by a rotation magnetic field generating device to the magnet in the capsule endoscope, the capsule endoscope and the spiral protrusion are rotated so as to generate a drive force for the capsule endoscope. Accordingly, the capsule endoscope is magnetically guided to a desired position in the subject.
Such capsule guiding systems include a system in which the magnetization direction of the magnet incorporated in the capsule endoscope and a reference plane direction of an imaging device (for example, the upper direction of a light-receiving surface) are relatively fixed. The capsule endoscope sequentially takes in-vivo images while making a rotation movement following the rotation magnetic field. The rotation of in-vivo images caused by the rotation of the capsule endoscope is corrected by image processing, and in-vivo images not rotated are sequentially displayed on a display device (see Japanese Laid-open Patent Publication No. 2003-299612 and Japanese Laid-open Patent Publication No. 2006-149668, for example).